This invention relates to liquid compositions. More particularly, this invention relates to liquid compositions containing photodecomposable complex salts.
In assignee's copending application Ser. No. 609,898, filed Sept. 2, 1975, incorporated herein by reference, there is described a photocoploymerizable compositions containing (a) an organic material containing expoxide functionality, (b) an organic material having hydroxyl functionality, and (c) a complex salt photoinitiator selected from aromatic iodonium complex salts and aromatic sulfonium complex salts. Such photocopolymerizable compositions are very useful for providing cured coatings on a variety of substrates for decorative or protective reasons. Such compositions are typically coated and cured by the manufacturer of the finished article, e.g. beverage can, label stock, coated paper, etc. Each such user of these compositions typically specifies the particular physical characteristics which the curable composition, and the cured coating, must exhibit for his particular applications (e.g. color, chemical resistance, coating characteristics, etc.).
Although such photocopolymerizable compositions may be formulated by each industrial user so as to meet his specific requirements, it is much more common for such compositions to be prepared by coating formulators who specialize in the preparation of coating compositions for industrial use. The coating formulators must procure the various necessary ingredients (e.g. base resins, colorants, viscosity modifiers, curatives, etc.) from a number of different sources. With respect to the photocopolymerizable compositions referred to above, it would be highly desirable to be able to supply the coating formulator with a concentrated solution of the complex salt photoinitiator in a form which would permit ready addition to, and compatibility with, a variety of different coating compositions (particularly those which are based on cationically polymerizable materials).
In an earlier filed application, Ser. No. 876,115, there is suggested the use of certain neutral oxyethylene-containing material as a solvent for certain sulfonium complex salts. Although such compositions claimed therein are quite useful there are some limitations with respect to the use thereof. For example, concentrated solutions of aromatic iodonium complex salts in such solvents have limited shelf life. The oxyethylene-containing materials generally have marked affinity for water therefore requiring particular care in the preparation of the complex salt solution to insure absence of all water and caution on the part of the coating formulator in the handling of the complex salt solutions.